The present invention relates to a strobo electron beam apparatus which provides a retarding field type energy analyzer for measuring a voltage and which quantitively observes the waveform of the voltage in the examined integrated circuit operated rapidly, and especially to the strobo electron beam apparatus which quantitizes the voltage waveform by controlling the retarding voltage supplied to the energy analyzer connected to a phase scanning operation.
As the method for quantitizing the voltage waveform in the integrated circuit by using strobo beams, the method for obtaining the voltage waveform with a one phase scanning operation (one time phase scanning method) is known. (Unexamined Japanese patent publication (Kokai) No. 59-225539 and No. 60-10739).
As the method for measuring the voltage waveform in the integrated circuit via an insulation film, a plurality of times phase scanning method and a precharge (erase) method using a serial scanning are known. (Unexamined Japanese patent publication (Kokai) No. 117640)
However, in the one time phase scanning method, a large amount of EB radiation is carried out at a same time and at one phase point, and accordingly, the voltage waveform measurement via the insulation film is difficult because of the charge up phenomena of the insulation film. Further, in the one time phase scanning method, if the metal wiring portion is directly probed, contamination is increased and thus the base line is displaced. Accordingly, a stable measurement of the voltage waveform is difficult when the base line sampling is not carried out.
The precharge method (Unexamined Japanese patent publication (Kokai) No. 60-117640) can quantitize the voltage waveform by cooperating with the one time phase scanning method, but an erase operation is required and thus the measuring time is increased.
Further, in the usual serial plurality of time phase scanning method (Todokoro, Fukuhara, Japanese Society for Promotion of Science, Committee 132, (Electron and Ion Beam Science and Technology) 82, Research Document p 20 (1982), unless the radiated amount of EB per one phase scanning is decreased, the voltage waveform of the wiring under the insulation film cannot be obtained without the charge up phenomena occurring. If, in the usual plurality of times phase scanning method, the phase scanning is carried out at a high speed, to remove the effect of the charge up, the frequency response of the energy analyzer must be more than 10 MHz, and therefore the quantitization of the voltage waveform is difficult to realize.